1. Field of the Invention
The present invention relates to a flexible printed circuit board having a multilayer circuit, and more particularly relates to the flexible printed circuit board having a component mount section and a cable section which is connected thereto.
2. Description of the Related Art
Printed circuit boards in electronic devices are used for mounting electronic components and connecting circuits, comprising the electronic components, by means of circuit patterns. A flexible printed circuit board is generally used as a printed circuit board for miniaturized electronic devices.
In miniaturized electronic devices, solid component mounting is often required to make the device more compact. To achieve solid component mounting, the present applicants provided a printed circuit board which combines a thick component mount section with a thin bendable cable section (Japanese Patent Application 284240/1999).
FIG. 2 shows the cross-sectional view of this type of flexible printed circuit board. A cover film 2 is pasted on each side of an inner-layer material 1, which has a circuit pattern on each side, and an outer-layer material 4 is provided over the cover films 2 of the component mount sections with an inter-layer adhesive 3 therebetween.
In this printed circuit board, the cover film is pasted over the outermost layer in order to insulate and protect the cable. Since positioning becomes difficult when the cover film is pasted only over the cable section, the cover film is also pasted over the component mount sections. As a result, the thickness of the flexible printed circuit board includes the cover film.
However, there is a constant demand for thinner and smaller miniaturized electronic devices, especially portable ones. Consequently, there is a demand to reduce the thickness of the cover film.
The present invention has been realized in consideration of the points mentioned above, and aims to provide a flexible printed circuit board which has a smaller overall thickness and a method for manufacturing the flexible printed circuit board.
In order to achieve the above objects, the present invention provides a flexible printed circuit board comprising a component mount section, which an electronic component is mounted on, and a cable section, which connects to the component mount section; circuit patterns being provided on the cable section and covered by a soft laminating adhesive.
The present invention also provides a method for manufacturing a flexible printed circuit board having a component mount section, which comprises an outer-layer material laminated on an inner-layer material with an insulating cover therebetween, and a cable section, which comprises the inner-layer material covered by the insulating cover and connects to the component mount section. The method comprises covering the inner-layer material of the component mount section and the cable section with a soft laminating adhesive.